A novel ball-in-ball hollow NiCo2S4 sphere based sensitive and selective nonenzymatic glucose sensor

In this work, we developed a low-cost and sensitive electrochemical sensor for nonenzymatic detection of glucose based on ball-in-ball hollow ternary nickel cobalt sulfide spheres (NiCo2S4). A facile anion exchange method to synthesize the hollow structure of NiCo2S4 is demonstrated. The synthesized hollow NiCo2S4 was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The electrochemical sensing properties of NiCo2S4 towards glucose were evaluated. Due to the synergetic effects from both Ni and Co species with multiple valence transitions and the high surface area of the hollow NiCo2S4, the nanostructure exhibited good performance towards glucose oxidation. A simple and selective sensing platform for the assay of glucose has been developed in 0.1 M KOH solution at 0.55 V. The sensor displays a wide linear range from 0.005 to 2 mu M with a detection limit of 2 mM for glucose detection. For the determination of glucose in serum samples, the results are satisfactory when compared to those obtained from a local hospital.